Editor's Note: Brenna Ehrlich and Andrea Bartz are the sarcastic brains behind humor blog and soon-to-be-book Stuff Hipsters Hate. When they're not trolling Brooklyn for new material, Ehrlich works as a news editor at Mashable.com, and Bartz holds the same position at Psychology Today.

(CNN) -- Dealing with other people is hard enough IRL ("in real life," for those among you who are not abject tech geeks). Add social media into the equation, and you have myriad opportunities to make enemies and alienate people.

But fear not, we'll show how to apply LinkedIn, Twitter, Facebook and Foursquare to the sundry folk you meet in your wanders.

Listen and learn, unless you prefer MySpace -- then you're a lost cause.

Situation No. 1: You make a legit business contact at a network event (before spilling your drink on an intern). You arrive home, business card clutched in your damp, shaking hand.

Do you add them on ...?

LinkedIn: Go for it. This social networking site is basically a digital Rolodex. Although you might not have a pressing reason to e-mail this contact the day after meeting him, adding him on LinkedIn reminds him that you exist in case he, too, got sloshed at said networking event.

Twitter: Proceed with caution. Dunbar's Number claims that we can be friends with only 150 people at a time, a concept that applies to social networks: If Joe Business has 50 Twitter followers, they're probably all inner-circle; if he has 150 or more, he probably views Twitter as a business tool.

Facebook: In most cases, hell, no. Unless homeboy has more than 1,000 friends. But then you have to ask yourself if you want to associate with what is commonly known as a "friend whore."

Situation No. 2: You make a new friend! Yay! Friends are life's gifts! Or something. Whatever.

LinkedIn: Hell, no. No one likes to make a new bud, only to discover that he was being "networked" all along.

Twitter: Proceed with caution. It's fine to keep up with your buds on this microblogging site, but we suggest hanging out with your new bro three or four times before getting all up in his lifestream. Unless you're an agoraphobe, and then you're on your own (literally).

Foursquare: Proceed with caution. After you hang out (shoot for three times in a month), it's OK to add someone on this location-based tool. While your new bud might not be the first person you text when embarking on a night out, your respective groups might be keen to hook up along the way via nearby check-ins. It's the equivalent of a late-night "What are you up to?" text.

Situation No. 3: You're perusing the stacks at your local used bookstore when you brush hands with a dark-eyed dreamboat. She's a doctor. You enjoy being stethoscoped.

LinkedIn: Hell, no. However, feel free to check the suitor's LinkedIn profile to ensure that she is not a dirty liar.

Twitter: Hell, no. You don't need to follow someone on Twitter to read her tweets (unless they're protected, in which case, what is she hiding?). Snoop silently for now.

Facebook: Proceed with caution. Facebook friending someone you're dating fuels angst: Who's that dude on her wall? Why does she have time to change her status but no time to text me back? And the web-wide "like" button thing -- really, she "likes" this cat video from CollegeHumor.com? Inevitably, however, your date will friend you, and you must accept. Welcome to the beginning of the end.

Foursquare: Excuse me while I have a patronizing laughing fit. How many "serendipitous" check-ins until you get your "Stalker" badge?